Instructables

Amaze A Science Class with Elephant Toothpaste

video Amaze A Science Class with Elephant Toothpaste
This experiment shows the decomposition of hydrogen peroxide catalyzed by potassium iodide. The reaction is done in a tall graduated cylinder so that the foamy product shoots out very quickly in a tall cylindrical shape; hence, the name elephant toothpaste.

Materials:
tall graduated cylinder (at least 500 ml)
food coloring
Dawn detergent
30% hydrogen peroxide (H202)
saturated solution of potassium iodide (KI)
disposable gloves
splint (optional)

Hazards:

1. Wear safety goggles. Also, wear disposable gloves when pouring 30% hydrogen peroxide, as it is a very strong oxidant.
2. Do not stand over the graduated cylinder because steam and oxygen are produced quickly.

Procedure:

1. Place a garbage bag or other covering on the lab table and possibly on the floor.

2. Fill the vial containing potassium iodide with water. Cap and shake until all the potassium iodide is dissolved (This should now be a saturated solution of KI made with 15 grams of KI and water.) Set aside.

3. Put on disposable gloves. Pour 80 ml of 30% hydrogen peroxide into a graduated cylinder.

4. Add about 40 ml of Dawn detergent to the hydrogen peroxide. Swirl to mix

5. Tilt the graduated cylinder and drip red and/or blue food coloring down the sides of the graduated cylinder to make your toothpaste striped

6. Quickly add the saturated solution of KI solution and stand back Be sure to move your hand away from the top of the graduated cylinder quickly or the hot foam will get on your hand and arm.

7. You may place a glowing splint in the foam to test for oxygen, but do not drop the splint into the graduated cylinder. The splint will relight indicating the presence of oxygen.

Discussion:

The rapid catalyzed decomposition of hydrogen peroxide produces O2 gas which forms a foam with the liquid detergent:

2H2O2 (aq) -> 2H2O + O2 (g)
The I-1ion is a catalyst for the reaction. The brown color of the foam is evidence of iodine in the reaction. It will stain clothes, skin, and carpet

Disposal:

Leave the gloves on while cleaning up. The foam and solution left in the graduated cylinder may be rinsed down the drain with excess water.

referance-http://library.thinkquest.org/10429/low/cool/labs/elephantlab.htm
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yellowbrain4 years ago
A few words on this experiment and Hydrogen Peroxide. Firstly if you are wishing to try this experiment I highly recommend you use Magnesium Dioxide as the catalyst instead of Potassium Iodide, It doesn't stain everything it touches like Iodides do. (also most metals work well as catalysts, Iron, Silver, copper all are really good, try iron filings :D) Secondly, Hydrogen peroxide above 6% is quite hard to obtain if you are not buying it from a chemical supplier, as a researcher, or business. 100% hydrogen peroxide essentially doesn't exist, at that concentrations near to 100% it decomposes explosively, and as such is near impossible to obtain anything higher than 70%. If you attempt to concentrate Hydrogen peroxide from a 3% or 6% solution, by evaporating the water (H2O2 boiling point is 15oC) you will in fact reduce the concentration as at higher temperatures the peroxide will decompose exponentially higher. Also be aware that peroxide is acid stabilized (a small amount of acid is added to prevent decomposition) and at pH of about 10 it will decompose on it's own in a matter of days. Good suppliers of lab grade (30-35%) peroxide are VWR and Sigma Aldrich, though these companies will definitely not sell to kids (under 18's) or to persons without legitimate reasons (for example I work in research of peroxide sterilization). Hydrogen peroxide, particularly of this grade is controlled as it is a precursor to a number of explosives. Hope this helps answer the questions which seem to appear in the comments If you wish to know more about Hydrogen peroxide, the following text is fairly comprehensive: "Hydrogen Peroxide" Schumb, Wentworth, Satterfield. 1955 ASC Monograph 128. (can be a bit hard to find however)
You can actually get 20, 30 even 40% H2O2 easily from a beauty supply shop. My 14 year old went in and bought it without any questions! >:-(

http://www.sallybeauty.com/40-Volume-Developer/SLNCAR67,default,pd.html
http://www.sallybeauty.com/Clear-Developer/SLNCAR61,default,pd.html
The links provided are for 20 and 40 vol peroxide.
The vol system is not the same as the % concentration.
the vol is the volume of oxygen generated when the volume of peroxide is decomposed.
So for a 1 liter solution of 40 vol (12%) peroxide this produces 40 liters of oxygen when decomposed.
As a guide each 1% is about 3.3 vol.

This is however a higher concentration then I expected to be available.
thankyou for your reply.
Screamo3 years ago
Front picture looks weirrdd
jumpertoad4 years ago
this is so totally awesome
nfarrow4 years ago
Looks like something from, "Demolition Man" with the car seen. LOL
andi65 years ago
Can't wait to try this!
WOAH! THIS IS SOOOO COOL!!!!!!!!!!!!!! mmm. I'm with the gorilla kid, where can we buy this stuff? Online...?
you can get weak peroxide from most pharmacies, it is sold as antiseptic
i think think you might be able to get the stuff at united nuclear.com, and they have a bunch of other cool stuff too.
think hindenburg. no shipments for you!
well then. i suppose not. i had some szechuan chicken the other day. it was yummy in my tummy.
you are a fish. i am the sun. I EAT YOU!!!
hmm... i never knew the sun had a digestive system. learn somethin new everyday dontchaaa?
well, i was actually going to roast you for my wife, Uranus
you are a funny one.
thank you, snakehead
actually. i'm a male jawfish. take THAT!
you smell like old people and snake poo, so i assumed you were a snakehead. it's only logical.
ouchie.
sorry smelly.
no not online shipments of h2o2 over 7% are highly dangerous. when it is mixed with organic substances at significant concentrations, hazardous impact-sensitive compounds may result. Small amounts of other materials that contain catalysts (silver, lead, copper, chromium, mercury, and iron oxide rust) can cause rapid decomposition and an explosive pressure rupture of the containing vessel if it is not properly vented.
check out what hydrogen peroxide does to your skin:

http://www.rocketbelts.americanrocketman.com/HP/HYDRO_PEROXIDE_BURNS.jpg

Tanners5 years ago
it would be cool if you mixed helium somewhere in there and then it could make the bubbles float!
IX Smith XI5 years ago
Ooooooooooo dang that is f**king cool. Five stars
lol thats cool. but it would have been cooler if you would have caught the stuff on fire xD.
if you wan't flaming bubbles try pumping propane through a garden sprinkler in a bucket of soapy water. Or, if you can find it, hydrogen! since it's lighter than air, you'll have a tower of highly flammable foam!
That was on Mythbusters!
actually, i lied, it was methane not hydrogen. but hey! methane is easier to get than hydrogen. just hook it up to your natural gas line. i love playing with fire XD
I forgot haven't seen that one in months. But yeah, playing with fire is awesome.
>_<
What?
i have had bad experiences with fire...
>_<
I just try not to burn myself or my house down....
chicken! bawk bawk bawkaw!
Oh sure, I'm a chicken because I like living in a house.
boxes are cheaper. also bigger than your house anyway.
Why are you making fun of me?
i'm not trying to be mean, just joking. btw, nice dog. i have a black lab & mystery fox terrier mix.
It's alright.
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